What happened
A commercial pilot and one passenger, who was conducting moose counting research for the Alaska Department of Fish and Game, departed for an on-demand air taxi flight over remote terrain. The aircraft was equipped with two wing-mounted fuel tanks, each featuring an electric fuel gauge, providing a total of four hours of fuel.
After approximately two hours of flight using the left fuel tank, the pilot noted the fuel was nearly exhausted and switched to the right fuel tank. After flying for about 1.5 hours on the right tank, the engine suddenly stopped running. The pilot then switched back to the left fuel tank and managed to climb to an altitude of approximately 1,000 feet. However, after six minutes of operation on the left tank, the engine failed a second time.
The pilot identified an emergency landing site on a small, frozen pond characterized by drifted snow and slushy ice. During the landing roll, the aircraft entered deep snow, causing the airplane to nose over. There were no injuries to the pilot or the passenger.
The investigation
During the investigation, it was noted that the passenger had flown in the same aircraft two days prior to the accident and observed that the right fuel gauge was inoperative. She reported that the right fuel gauge remained inoperative during the flight involving the accident. Following the recovery of the aircraft, investigators found evidence of fuel staining on the upper surface of the right wing, located adjacent to the right fuel cap.